Quoted from LTG:

Even though you swapped opto boards, clean them.
Plungers move freely in coil ?
A tiny bit of up and down play on the flipper so the pawl isn't binding on the bushing below the playfield ?
LTG : )

Quoted from LTG:

The game will ignore them if you disconnect them. Forget them.
Your problem lies elsewhere.
LTG : )

Quoted from marcocapetown:

this is strange problem. im still learning about this stuff, but since i been messing with flippers abit and reading abit well here is why coils can overheat.
basically a coil has a high power side, that gives the "power" to the coil, but also has a lower power side. now on non fliptronics games the end of stroke is really important, cause it will be there to put on the lower power. like i had a problem of a weak flipper on the left on a Party Zone, so i just adjusted the end of stroke to come on almost at the end and it solved the issue.
on creature u have fliptronics board, so even if u cut out the end of stroke switches the coil wont stay up cause the low power side wont kick on and the board would make it cut out after like a few seconds.
but anyways right from the master himself clay. hopefully he wont mind me posting this, but hey full credit to him.
On WPC fliptronics and later games, if there is a marginal flipper switch reading, this causes the high powered side of the flipper to rapidly oscillate between on and off. The holding side of the flipper coil never engages. This problem will cause the flipper coil to get very hot in a short time. First try cleaning the flipper board optics. If this doesn't work, the LM339's on the Fliptronics board at U4 and/or U6 (or CPU board on WPC-95 at U25 and/or U26) will need to be replaced.
or
Bad regulation of the 12 volt power to the optos can cause the flipper coils to get hot too. Though rare, the 7812 voltage regulator on the power driver board could be failing, or the electrolytic filter capacitor for the 12 volts.

Quoted from Homepin:

The temperature of the coils could be subjective. Just how hot do they get? Hot enough to melt plastic?
Maybe there is no fault at all?

Quoted from silverball0:

Just a shot in the dark, but have you measured the voltage at the coils? You may be pumping more than the 50 volts.

Quoted from jadziedzic:

You mentioned that you replaced the flipper opto boards; did you replace the entire assembly (board plus interruptor) or just the board? What color plastic are the interrupters? In some odd cases the (white) plastic is not entirely opaque which can cause enough light leakage to partially trigger the opto.

Quoted from scott_freeman:

how are the switches in test mode?
maybe you have some AC leakage across the circuits, giving you momentary open circuits?
set your DMM to AC, and check the critical DC circuits.
one other question, do the coils get hot with zero play after 10 minutes, or only with game play?
If the coils are fine without play, I would focus on binding.

Quoted from joe2012:

hi rygar,did you look at the coils?

Quoted from scott_freeman:

ok, since you swapped the fliptronics board, (thanks lloyd for confirming it has the LM339s'),
your swap rules out the LM339's, and the rest of that board.
Ok, I'm back at mechanical binding.
Care to swap one complete flipper assembly bewteen your two games?
If your heat issue follows the assembly, you know where to focus.
I'm still thinking binding.
just a reminder, both the coil stop, and the small bracket holding the coil, need to be seated squarely. (90 degrees to the axial line of the coil)
Don't let either bracket walk/turn while tighting down their fasteners.

Quoted from 0geist0:

This may have already been covered, but I had a similar problem with a Flintstones. Somebody had put two return springs on the flippers, and I just didn't notice it, and that caused them to get very hot.

Quoted from scott_freeman:

ok, since you swapped the fliptronics board, (thanks lloyd for confirming it has the LM339s'),
your swap rules out the LM339's, and the rest of that board.
Ok, I'm back at mechanical binding.
Care to swap one complete flipper assembly bewteen your two games?
If your heat issue follows the assembly, you know where to focus.
I'm still thinking binding.
just a reminder, both the coil stop, and the small bracket holding the coil, need to be seated squarely. (90 degrees to the axial line of the coil)
Don't let either bracket walk/turn while tighting down their fasteners.

Quoted from Big70:

I'd agree with the others to look at the flipper opto boards, but if you'd tried 3 sets (all of them with clean optos correct?), you can pretty well eliminate that as the issue. The next place would be to look at board issues, but you've eliminated board problems by swapping in good known working boards. If you've indeed already replaced the CPU, Driver board, flippertronics board, flipper opto boards, and even the transformer with known good working ones (plus new coils, EOS switches), you've eliminated all of them as the issue. That only leaves me to think you've got a wiring problem somewhere.
You might try swapping ribbon cables to eliminate those as an issue since they carry the data for the logic. Bad ribbon cables can cause all sorts of weird problems.

Quoted from scott_freeman:

ok, this should eliminate binding.
boards and LMM's were eliminated.
and the coils are cold when not played.
Now, I'm thinking your grounds are not good.
The problem needs to be with something that is common to the two flipper assemblies.
You should have zero voltage when measuring across your grounds.
Also, no AC ripple in the ground circuits (set DMM to ACC for this)
even more challenging, you need to measure across the grounds when the flippers are actuated.
oh, and just for the record, what version ROM are you running? (seeing if you have a prototype ROM)

Quoted from yonkiman:

I just read through this thread quickly but don't recall seeing this mentioned - maybe you have the hold coil and the power coil reversed at the lugs. Take a photo of your coils as installed on your CFTBL, then measure the voltages on the 3 terminals of the coil with the flipper energized and let us know what the voltage on each terminal is with respect to the terminals shown in your photo.
This almost has to be the problem - it's the only way the game could be playable with a known good fliptronics board and still have coils overheating.

Quoted from Atomicboy:

I think you're alright. Coils get warm, in fact hot to the touch in many cases, especially on games that play more low and down, such as CFTBL and IJ. I went through a similar thing with my IJ flippers a long time ago, and I cold not figure it out. It just seemed like to the touch, they were hotter than other coils of the same WPC era. In the end, I just attributed this to the game design, and that all in all, there are more flips on some machines than others.
Take LOTR for example. I know it's a different system, but it has some much more flipper action than most sterns, and because of this is suffers more than any other machine with this same issue, coils working fine but heating up. In that case, the heat is enough to unglue the stickers for the coils. People have done all kinds of crazy mods from heatsinks to computer fans to deal with that machine. Different design altogether, but its to show that flippers can have this happen, and it's acceptable all in all.
Try taking another WPC89 flip II game you have and starting each cold, and say for the left flipper only, flip each 100 times, measure the heat with whatever you are using, then 200 times. I'm guessing this will come out to be close.
CFTBL sees a lot of quick and low play. It's hard to realize how many more times you might be flipping, but take a worst case scenario of you constantly flipping one flipper coil fast for a while, it's going to get quite hot on any machine.

Quoted from yonkiman:

Based on what you've said you swapped, I only see two remaining scenarios:
1) CFTBL coils just get hot under normal operation, or
2) Your wiring harness is incorrectly swapping hold and power coils. That's very unlikely, but you can check the wires on J907 and J902 and make sure the colors match the schematic below.
But if the left and right coils are behaving identically...maybe the heat's just normal? Would still be interested in the coil voltages when the flippers off and energized. Also you could remove J902 and measure the resistance between the top (common) winding and the power and hold terminals. To eliminate any possible effects from the diodes, measure the resistance one way, then reverse the ohmmeter leads and measure it again. If the readings are different (they may or may not be depending on your ohmmeter's characteristics), the higher reading is the correct one.

Hello.
At 1) I will measure the temperature on two games under identical conditions like Atomicboy suggested to see if that is normal.
At 2) I will check the wiring harness. I will also measure coil voltages. I will also measure the resistance like you have suggested. My current multimeter is not a state of the art one, but for this measuring will borrow one that has better characteristics.

Thanks!

right_coil.jpg 55 KB

Quoted from LTG:

Long shot. I was wondering if the transformer in your game is a different herz, then what should be in your game ?
LTG : )

Quoted from Marten:

Just out of curiosity, what makes the difference between heating and overheating in this case.
Is it that things have stopped working right,
does the coil manufacturer give a maximum operating temperature,
is smoke coming off them or
are things melting/ blackening?
Otherwise just play and don't worry too much.
If it ain't broke, don't fix it.

Quoted from yonkiman:

And ultimately you found the root cause to be the transformer? I've seen lots of unexpected things in electronics, so I can't say that's impossible, but it's hard to understand how a failing/bad transformer could cause a coil to overheat. I guess if there were somehow shorts in the primary making the number of effective windings lower, the output voltages would be higher. I'm very interested in this because I love an (electronic) mystery, and this certainly seems to be that.
It is interesting that my AFM has plenty of power for that light lock shot, but my HS2 only barely makes it around the back and up the ramp to lock a ball. They both use the same coil and have rebuilt flippers. I don't think it's a coil heating issue (it has the problem when I power on), but thanks for reminding me to revisit it! I need to check the power supply under load...

Quoted from Schwaggs:

rygar, did you rebuild the flippers with new mechanical components? I couldn't find this in the thread so I thought I would ask. With the slightly elevated temps of your coils, if the flipper plungers are mushroomed a little bit, it could cause the flipper to weaken when warmed up. I had this problem with my I500. The flipper plungers looked and felt normal but a quick filing around the edge of the end of the plunger cured it. File it to a nice taper around the edge of the end.

Quoted from terryb:

I could be wrong, but the contacts on those eos switches don't look right. They should be gold plated contacts. Also it looks like the two contacts (on the same switch) are of different sizes. While I'm not sure it's likely, I do think it's possible that if there's high resistance across the eos it could be confusing the fliptronics board into providing high power when it shouldn't be.
I know you switched the flipper mech around, but maybe the other game didn't stress it enough, or small variances in the way the fliptronics board works.
If that doesn't do any good I would break the blu-yel wire on one of the flippers and put your meter across the two sides (meter set to current). Then check the current reading with the static flipper position, the high power position and the hold position. To check the high power position you will have to keep the flipper from traveling far enough to hit the eos switch.
Compare this to another game.

Quoted from terryb:

I could be wrong, but the contacts on those eos switches don't look right. They should be gold plated contacts. Also it looks like the two contacts (on the same switch) are of different sizes. While I'm not sure it's likely, I do think it's possible that if there's high resistance across the eos, the board could be thinking a ball hit the flipper and then re-energize the power circuit unnecessarily.
If that doesn't do any good I would break the blu-yel wire on one of the flippers and put your meter across the two sides (meter set to current). Then check the current reading with the static flipper position, the high power position and the hold position. The high power circuit will only energize briefly before the board turns it off so it will be hard to catch unless you have a pretty good meter.
Compare this to another game.

Quoted from doctor_pinball:

check your wall outlet voltage VAC check the input transformer connector as the jumpers not to be set on 103,5 vac instead of 115 vac ,,,,,,,,,,,this might be an issue which raise your coil Vcc at 75 V ,, how hot is the CFBL transformer compared with the RS transformer ??
And a personal reply I have no playfields for Shadow ,,,sorry !
EOS contacts does not matter on fliptronic are used only to change lanes CFBL has a 15411 coil and a 11629 which will take a little more current than 15411 on the force winding
Reading up that you swapped the trafo an ultimate ideea check trafo color wires with the RS trafo at the input connector wires not to be reversed by the previous owner this seem paranoic but probably is last call

Quoted from terryb:

Checking the voltage jumpers as doctor_pinball said is a good idea.
Do both games use the same coils? I forget if it's been covered, but have you verified you have the correct coils?
Have you tried another fliptronics board? It's possible the board could be causing the problems.